Vinyl resin phonograph records



Patented Jan. 5, 1943 VINYL RESIN PHONOGRAPH nnconps Victor Yngve, Lakewood, Ohio, asslgnor to Carbide and Carbon Chemicals Corporation, a corporation of New York No Drawing.

Application September 12, 1940,

Serial No. 356,500 7 Claims. (Cl. 260-9) This invention relates to improvements in fillers for use in vinyl resin phonograph records whereby records characterized by a very low surface noise level and by exceptionally long life and durability are produced.

Filling materials of various kinds have been proposed for use in vinyl resin molding compositions for phonograph records and in such compositions they serve the dual purpose of reducing the costof the record and of-increasing its resistance to wear during playing. However, it has heretofore proved impossible to incorporate large amountsof these fillers in the molding compositions without causing an'undesirable degree of surface noise when the record is played on sound reproducing machines having high amplification and tone fidelity. Moreover, irrespective of the type of filling material used, objectionable features exist when large amounts of fillers are incorporated. Thus, abrasive materials are satisfactory in strengthening the record against wear but cause an undue amount of surface noise and non-abrasive materials are unserviceable from the viewpoint of either the initial surface noise of the creases after playing on account of excessive wear of the record.

It has been found that the above disadvantages may be overcome by the use of certain mixed fillers in regulated proportions in the vinyl resin records. One of these fillers is composed of finely-divided cellulosic or ligno-cellulosic materials and the other consists of finely-divided inorganic substances of an abrasive nature. The cellulosic or ligno-cellulosic materials are characterized by a low density so that they do not increase the weight of the record. At the same time, these products mechanically reinforce the record but do not increase the consistency and stillness of the composition to a point where molding becomes difficult. Examples of cellulosic or ligno-oelluloslc materials are wood flour, cotton flock, finely-divided cellulose, peach shell flour,

'perlment that not all inorganic fillers are suitable to combine with the celluloslc or ligno-cellulosio materials in the amountsrequired for making a satisfactory mixed filler. Thus, relatively soft and non-abrasive materials such as finely-divided clay or talc were found to be undesirable in large quantities from the view of either durability or surface noise. It has been determined that at least the major portion of-the inorganic filler should be composed of substances having an abrasive nature similar to pulverized silica or to di-- atomaceous earth. Abrasive fillers are understood to be those materials having a hardness of at least 5 on Mohs scale of hardness and other examples of such materials are anorthite, a lime feldspar, andesine, a calcium sodium feldspar, and anorthoclase, a sodium potassium feldspar.

As a direct result of the use of the mixed fillers of this invention, the weight ratio of filler to vinyl resin may be in excess of 0.60 with a consequent decrease in the cost of the record and with an actual gain in its playing qualities. However, to obtain records of good performance, particularly with respect to their surface noise level, when large amounts of the mixed filler are employed, it is essential that both the cellulosic or ligno-cellulosic fillers and the inorganicabrasive fillers be minutely subdivided to particles that will pass a 1 standard 200 mesh screen and preferably a standard 300 mesh screen. Since the standard com-- mercial grade of fillers is ordinarily not of such-a fine particle size, special grades must be secured-. As indicated previously, the ratio in which; cellulosic or ligno-cellulosic fillers and the, in-v organic abrasive fillers are combined in the mixed filler is of great significance since neither typeofv filler used singly is satisfactory. It has been 1 found by test that, from the standpoint of both; resistance to abrasion and the surfacenoiselevel; of the record, suitable volume ratios of thercell u losic or ligno-cellulosic filler to the inorganic abrasive filler are between 75:25 and 40:60. These tests were carried out using record compositions having the same vinyl resin content and and apricot shell flour. It has been found by exthe same total filler content by volume in which the ratio of the two types of fillers was varied with success in the production of sound records widely. are as follows:

In testing the records, initial noise level was determined by playing the record and where improvement was noted. it was or such magnitude 5 as to be plainly discernible to the ear. Any in- A n crease in noise level after playing was determined by playing back a portion of the record 15 times Conloint poi or of Puma Pom by Psmby you by and then comparing its noise level at that point 112 am?" 5 y g with the noise level of an unplayed section of the wwi'noun-sdifiiiiiiii'. 221s 24.1 1110 l is. record. This was repeated in increments of 1 I m playings. Any record wear was determined at the ass 1.: o. as 1 same time in this series of tests by noting any distortion of the recorded sounds and by visual inspection of the record with the aid of a mag- 15 nifylng lens.

The results of the tests were as follows: These formulations may be modified b he Composition of mm lnitinl T1 Noise level w n 8% Dlutomm 5:22? rim 335 fi st? Wood flour 8323? Percent by Permit by volume volume 100 0 High 15 Very high. Vet high.

70 Low 150 Low Biig t. as do 150 .....do Do. 30 Medium. 160 Increased.-. Do. 0 ...do do Do.

The above test results bring out the interesting inclusion of plasticizers and pigments as follows: fact that the use of the mixed fillers in the pro- 39 portions set forth produces a vinyl resin record P b 1 having qualities superior in every respect to new records which contain either of the fillers singly. C D

The vinyl resins employed in the above tests and which are preferred in the practice of this 40 invention are those described in the Grofl Patent a as: 4 No. 1,932,889. These resins are conjoint polymers of vinyl halides with vinyl esters of aliphatic mesh &3 3 acids having combined vinyl halide contents in ggggg ggmg &: as excess of 70% by weight. A particularly deslr- White lea 10 able resin of this class is a conjoint polymer of black vinyl chloride with vinyl acetate containing 87% I vinyl chloride by weight and having an average Records may be fomd fr m these composb macromolecular weight of about 10,000 as deterby fir t mixing the ingredients on a heated mined by Staudingers method. Less desirably, 5o rubber m or m a heated dougmtype mixer until other vinyl resins may be employed as the base homogeneous and then pressing the composition f the Sound r r Such as t m re h h into prefer-ms. This latter operation may be p ym r e polyvinyl acetate resins and the performed at temperatures of from to 150 resins formed from them by their partia 1111- c. and at pressures up to 2000 pounds per square drolysis and subsequent reaction with aldehydes. 65 h, The impression of the sound groove is then In the production of the molding compositions accompl shed by pressing the heated preforms for forming the records a wide variety of the cusagainst an appropriate die. Records'having the ry plasticizers. Waxes. lubricantsheot above formulations are representative of those lli r and P n m be includedw v which exhibited the excellent characteristics in because of the large amount of the mixed fillers th t t previously described, which are incorporated in the compositions of no Modifications within the designated limits of this invention, certain plasticizers have been the formulatio d ib d i t examples and fou d t e p r a y e c ve in creasin the addition or substitution of other ingredients the p s c o t e c mp sit o d r s mo din are permissible without departing from the scope These are alkyl-substituted phenanthrenes, such 06 of the invention as deiinedby the appended as retene (l-methyl, 'l-isopropyl phenanthrene). claims. and the fatty acid pitches remaining as a residue This application contains subject matter in from the distillation of fats, oils and waxes. common with my copending application Serial These pitches are dark in color and the prefer- No. 356,525, flied Sept. 12, 1940. able ones for use in this invention have softening 70 I claim: points of about F. Both of these plasticizers 1. A molding composition for phonograph are desirably used in amounts ranging from about ords comprising a base of a vinyl resin, composed 5% to about 25% by weight of the vinyl resin of a conjoint polymer of vinyl chloride with a portion of the record. vinyl ester of an aliphatic acid. and substantial Typical formulations which have been employed :5

amounts of mixed filled composed of from '75 to material having a hardness of at least on Mohs 40 parts by volume of one-oftthe group consisting of finely-divided cellulosic and ligno-cellulosic materials and 1mm 25 to 60 parts by volume oi" a finely-divided inorganic abrasive material having a hardness of at least 5 on Mohs scale of hardness. both ingredients of said mixed filler being substantially of such a degree of fineness as to pass a standard 200 mesh screen. 7

2. A phonograph record comprising a base of a vinyl resin, composed of a conjoint polymer of vinyl chloride with a vinyl ester of an aliphatic acid, and at least 0.6 as much by weight of a mixed filler composed of from 75 to 40 parts by volume of one of the group consisting of finelydivided cellulosic and ligno-cellulosic materials and from 25 to 60 parts by volume'of a finelydivided inorganic abrasive material having a hardness of at least 5 on Mohs scale of hardness, both ingredients of said mixed filler being substantially of such a degree of fineness as to pass a standard 200 mesh screen. V

3. A molding composition for phonograph records comprising a base of a vinyl resin, composed of a conjoint polymer of vinyl chloride with vinyl acetate, and substantial amounts of a mixed filler composed oi from 75 to 40 parts by volume of one oi the group consisting of finely-divided cellulosic and ligno-cellulosic materials and from to 60 parts by volume of a finely-divided inorganic abrasive material having a hardness of at least 5 on Mohs scale of hardness, both ingredients or said mixed filler being substantially of such a degree of fineness as to pass a standard 200 mesh screen. i

4. A'phonograph record comprising a base of a vinyl resin, composed of a conjoint polymer of vinyl chloride with vinyl acetate, and at least 0.6 as much by weight of a mixed filler composed of from 75 to 40 parts by volume of one of the group consisting of finely-divided celiulosic and ligno-cellulosic materials and from 25 to 60 parts by volume of a finely-divided inorganic abrasive scale of hardness, both ingredients ofsaidmixed filler being substantially or such a degree of fineness as to pass a standard 200 mesh screen.

5. A phonograph record comprising a base of a vinyl resin, composed of a conjoint polymer of vinyl chloride with vinyl acetate, and substantial amounts of a mixed filler composed of from 75 to 40 parts by volume of-finely-divided wood flour and from 25 to parts of diatomaceous earth, both the wood hour and the diatomaceous earth being substantially of such a degree of fineness as to pass a standard 200 mesh screen.

6. A molding composition for phonograph records comprising a base of a vinyl resin, composed of a conjoint polymer of vinyl chloride with vinyl acetate, a small amount of retene as a plasticizer and a substantial amount or a mixed filler composed of from to 40 parts by volume of one or the group consisting of finely-divided cellulosic Y and ligne-cellulosic materials and from 25 to 60 parts by volume of a finely-divided inorganic abrasive material having a hardness of at least 5 onMohs scale of hardness, both ingredients of said mixed filler being substantially of such a de-' gree of fineness as to pass a standard 200 mesh screen;

7. A molding composition for phonograph records comprising a base of a vinyl resin, composed of a conjoint polymer or vinyl chloride with vinyl acetate, a small amount of avfatty acid pitch as a plasticizer and substantial amounts of a mixed filler composed of from 75 to 40 parts by volumeof one of the group consisting of finely-divided cellulosic and ligno-cellulosic materials and from 25 to 60 parts by volume of a finely-divided inorganic abrasive material having a hardness of at least 5 on Mohs scale of hardness, both ingredientsoi said mixed filler being substantially of such a degree or fineness as to pass a standard 200 mesh screen.

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